Good judgement, I guess
TWIXT PP

I discovered the following end of game position while browsing games in Game Center.

Black is to move. At first, I thought black resigned in a winning position, but upon closer examination I believe white was winning after all, because white can play O13 which starts a new threat on the top right and simultaneously improves the connection to O18. Am I wrong? Is black actually winning here?

I don’t find anything for red (white) after 25.U6 26.T8. I added that line to the commentator (link above.) The R4 variation seems to last longer, although hypercube likely would not have been fooled.

The underlying theme here is about games where resignation may have been correct, but there were still resources the resigning player might have used. So in the first diagram Black could have tried K14 threatening black M18 or black G13, and under a fast time control maybe white would have missed O13 covering both threats.